Workers at a local op shop say they are in shock after finding a mutilated kangaroo in their skip bin.

About 12.15pm on Thursday, Make a Wish team members Isabelle Morrow and Loreen Truman were having a break outside the store when a white ute pulled up in the car park.

A man grabbed a box from the car and dumped it in the shop’s skip bin.

Ms Morrow said she asked the man if he wanted to make a donation to the store, since donations should be made inside the premises.

He replied it didn’t matter since the box was “just a small donation”, before getting in the car and driving off.

When the team opened the box to retrieve the donation they made the gruesome discovery; several freshly amputated kangaroo legs.

“We said maybe we will go and have a look, maybe it’s something for us to sell,” she said.

“It was a shock.

“I called them a lot of names because we didn’t expect that.”

Make a Wish team member Christine Hodges said the store would have to bear the cost of the disposal of the remains, since animal remains could not be mixed with regular waste.

“It’s another fee that we have to pay again,” she said.

“It means the kids will miss out on something because we have to pay for that extra fee for them to come out and get it.”

“It’s very upsetting,” Ms Morrow said.

“Lots of people just don’t think the consequences after somebody has dumped something.”

Mandurah police, the RSPCA and the Department of Health have been notified.

RSPCA WA chief inspector Amanda Swift said it was strange someone would leave the legs in a charity bin.

“It’s a bit bizarre that anyone would think this is acceptable,” she said.

“It’s difficult to establish the circumstances around how these poor animals may have died or whether they suffered any cruelty, but if anybody has any information about how the kangaroos may have been killed, please let us know.

“You can call RSPCA Cruelty line on 1300 278 3589.”

The store is also calling on anyone who might have dash-cam footage of the ute driving nearby to contact them immediately.

The car was a white utility with a washing machine strapped to the back.

Penalties for cruelty to animals under the Animal Welfare Act (2002) include a fine of up to $50,000 or imprisonment for up to 5 years.